/Engine/Source/Editor/BlueprintGraph/Classes/K2Node_CallFunction.h
Routine for validating that all UPARAM(Required) parmas have a connection:
void ValidateRequiredPins ( const [UFunction](API\Runtime\CoreUObject\UObject\UFunction) * Function, class [FCompilerResultsLog](API\Editor\UnrealEd\Kismet2\FCompilerResultsLog) & MessageLog ) const